The properties of the atmospheric aerosols depend on the source region and on the modifications that occur during their transport in the air. We have studied physical and chemical properties of aerosols along with their sink mechanism over two locations in southwest India, an urban site (Pune) and well-established climate observatory at Sinhagad (SINH), which represents rural and high altitude site. The ground-based measurements of aerosols, together with their radiative properties in this study have provided means to understand the observed variability and the impact on the aerosol radiative properties effectively over this region. The annual mean elemental carbon concentration (3.4 µg m − 3 ) at Pune was observed about three times higher compared to SINH (1.3 µg m − 3 ), indicating strong emissions of carbon-rich aerosols at the urban location. Aerosol optical properties were derived using the OPAC model which were used to compute the Aerosol radiative forcing (ARF) over both stations calculated using SBDART (Santa Barbara DISORT Atmospheric Radiative Transfer) model shows pronounced seasonal variations due to changes in aerosol optical depth and single scattering albedo at both locations. The year-round ARF was 4–5 times higher over Pune (31.4 ± 3.5 Wm − 2 ) compared to SINH (7.2 ± 1.1 Wm − 2 ). The atmospheric heating rate due to aerosols shows a similar pattern as ARF for these locations. The heating was higher in the wintertime, ~ 0.9–1.6 K day − 1 at Pune, and ~ 0.3–0.6 K day − 1 at SINH. The estimated scavenging ratio was found high for NO 3 − and Ca. 2+ . The wet deposition fluxes of Cl − , SO 4 2− , Na + , Mg 2+ were observed higher for SINH as compared to Pune, due to the high amount of rain received at SINH.

中文翻译：

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印度西南部大气气溶胶的物理化学特征和汇机制

大气气溶胶的特性取决于来源区域和它们在空气中传输过程中发生的变化。我们在印度西南部的两个地点研究了气溶胶的物理和化学特性及其汇机制，一个是城市站点 (Pune)，另一个是位于 Sinhagad (SINH) 的完善的气候观测站，代表农村和高海拔站点。本研究中对气溶胶的地面测量及其辐射特性提供了有效了解该地区观测到的可变性及其对气溶胶辐射特性的影响的方法。观察到浦那的年平均元素碳浓度 (3.4 µg m - 3 ) 比 SINH (1.3 µg m - 3 ) 高出约三倍，表明城市位置富含碳的气溶胶的强烈排放。气溶胶光学特性是使用 OPAC 模型得出的，该模型用于计算使用 SBDART（圣巴巴拉 DISORT 大气辐射传递）模型计算的两个站点的气溶胶辐射强迫 (ARF)。两个位置的反照率。与 SINH (7.2 ± 1.1 Wm - 2 ) 相比，全年 ARF 比浦那 (31.4 ± 3.5 Wm - 2 ) 高 4-5 倍。气溶胶引起的大气加热速率显示出与这些位置的 ARF 相似的模式。冬季供暖较高，浦那为 ~ 0.9–1.6 K day − 1，SINH 为 ~ 0.3–0.6 K day − 1。发现对于NO 3 - 和Ca，估计的清除率很高。2+。与 Pune 相比，SINH 的 Cl - 、SO 4 2- 、Na + 、Mg 2+ 的湿沉积通量被观察到更高，